1. Field of the Invention
This invention relates to an apparatus for needling a web, comprising at least one needle board, which has holes arranged in rows and adapted to hold needles, a backing disposed opposite to the needle board, and a stripper, which is disposed between the backing and the needle board, wherein said stripper and optionally also the backing consists of a perforate plate.
2. Description of the Prior Art
In order to ensure that a web will be uniformly needled the points at which the web is penetrated by the needles must uniformly be distributed over the width of the web so that the pitch of the needles in the direction of the working width of the needling apparatus must be uniform and the pitch of the holes of the perforate plate or plates used as the stripper and optionally as the backing must be uniform too and equal to the needle pitch. Because design considerations require a minimum distance between adjacent needle-receiving holes of the needle board and between adjacent needle passage holes of the perforate stripper plate and of the optional perforate backing plate, said requirements can simply be met in that the holes are arranged with a uniform hole pitch in rows having a uniform row pitch and the holes in adjacent rows are offset from each other. Because the uniform needle pitch which will be obtained with needles arranged in a regular pattern will necessarily be disturbed if individual needles or rows of needles are omitted, a change of the needle pitch will require a replacement of the needle board, of the stripper and of the optionally perforate backing if a uniform needling is called for.